The present invention addresses a low profile connector designed for surface-mounting. It especially relates to connectors mounted in the thickness of a printed board. More particularly, it finds use in the field of miniature electronic devices. It may particularly be used in the field of mobile telephony, for instance for connection between a battery and a printed board housed in a case of a mobile phone. Such a connector may also be inserted in an opening of a printed circuit board, formed in the thickness thereof. The invention provides very low thickness and low profile connections, while preserving a high-quality electric contact.
In prior art, connectors to be surface-mounted and connected on a first face of a printed board are known. These connectors have a contact for connection to a complementary connector. The contact is situated on the side of said first face of the printed board. In this case, such surface-mounted prior art connector forms a protrusion on the surface of the printed board whereon it is mounted. Further, from document U.S. Pat. No. 5,685,726, a connector is known which comprises a plastic member and contacts housed in holes of said plastic member. Each contact is housed in a separate hole. The plastic member, in turn, is placed in an opening of a printed board so that tabs of the plastic member are mounted on a first face of the printed board and that a second face of said plastic member protrudes beyond the second side of the printed board. Also, the contacts housed in the holes of the plastic member are such that a portion of these contacts is soldered on the first face of the printed board, and such that they have a second portion which is perpendicular to the plane of the printed board, inside the respective holes of the plastic member. Such plastic member has orifices opening onto the second face of the printed board, so that the second vertical portion of the contacts is accessible for connection to a complementary connector. Therefore, the coupling area of this connector is situated in the hole of the plastic member.
Prior art connectors, while providing a high density, involve a first problem. These connectors are quite complex, a complex shape having to be provided if a coupling area wholly protected inside a plastic member is needed. As a result, the shape of the contacts inside the plastic member is complex. In fact, a contact comprises a metal section curved at several locations to allow it, on the one hand to be soldered on a face of the printed board, and on the other hand to be held inside the plastic member and finally to have a perpendicular portion of the contact for connection to a complementary connector. This structure is provided to allow several connection-disconnection cycles. Nevertheless, it has a drawback in its being rigid and also bulky. In fact, due to the structure of the contacts, the plastic member cannot be wholly housed within the thickness of the printed board. Further, the tabs of this plastic member protrude beyond a first side of the printed board. Prior art connectors have a second problem. They require a considerable force for inserting the complementary connector, which may eventually cause embrittlement of the printed board, of the plastic member or of the connection between said plastic member and the printed board.
A connector as provided in this invention also comprises a plastic member and a contact element. Such a connector is arranged to be mounted inside an opening of a printed board, whether said printed board is flexible or rigid. The contact is such that it has solder tails on a first face of the printed board. These solder tails are preferably soldered on both sides of the opening on the first face of the printed board. Further, the contact has a flat portion between these solder tails, said flat portion extending in the width of the opening, in such a manner as to have a contact surface on the side of the second face of the printed board. This flat surface is raised with respect to the solder tails, and is connected to said solder tails by vertical piers. These vertical piers have a height of the same order as the thickness of the printed board. The plastic member of such connector has a shape complementary to the opening of the printed board which may be already provided with contacts. Like the height of the piers, the plastic member has a thickness of the same order as the thickness of the printed board.
Said plastic member has at least one orifice wherefrom the flat surface appears on the side of the second face of the printed board. The vertical piers are preferably disposed along a wall of the plastic member in such a manner that said wall is perpendicular to a plane formed by the upper surface of the printed board. Hence, such a connector has a flat contact surface flush with or slightly above or below the surface of the second side of the printed board. Said flat surface may also include a contact element, itself being rigid or flexible, to ensure connection with a complementary connector. In a first illustrated instance, the flat surface of the contact has a length which is smaller than the width of the opening of the printed board, whereas the plastic member has a central orifice, so that the flat surface and the vertical lateral piers of the contact may be inserted therein. In a second illustrated instance, the flat contact surface has a length which is equal to the width of the opening of the printed board, whereas the plastic member has side indentations for the passage of the vertical lateral piers of the contact, upon mounting thereof in said opening of the printed board.
Thus, the invention relates to a connector to be surface-mounted on a printed board, comprising at least one contact and one insulating plastic member of said contact, the plastic member being held inside an opening of the printed board, the contact being mounted on a first face of the printed board and having a contact surface on the side of a second face of said printed board which is opposite to the first face, characterized in that the contact forms a bridge consisting of a central contact portion and two tabs, so that the two tabs are mounted against the first face of the printed board, the central contact portion extending in the opening between said two tabs.